<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        /* 属性选择器 */
        /* 含有type属性的 */
        /*
        [type] {
            background-color: orange;
        }
        */
        [type="text"] {
            background-color: orange;
        }
        [name="userpass"] {
            background-color: lightblue;
        }
        [type="submit"] {
            background-color: lightgreen;
        }
    </style>
</head>
<body>
    用户：<input type="text" name="username">
    <br>
    密码：<input type="password" name="userpass">
    <br>
    <input type="submit">
</body>
</html>